Seismic braces including pin and collar connection apparatus

ABSTRACT

A connection apparatus includes a frame-side member securable to a steel structural frame, a brace-side member securable to a seismic brace, and a coupling element that secures frame-side and brace-side members to each other. By way of example, the connection element may provide a hinge-type connection, which substantially isolates a seismic brace from nonaxial loads. As another example, the connection element may be a ball-and-socket type connection, which substantially isolates a seismic brace from nonaxial loads and absorbs any shear and moment applied thereto when the seismic brace drifts out of an intended plane of the steel structural frame. The connection element may also include a collar to stabilize the brace-side member and prevent shears and moments from causing the same to buckle in an unintended direction. Methods of installing and using the connection apparatus are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 10/310,692,filed Dec. 5, 2002, now U.S. Pat. No. 6,837,010, issued Jan. 4, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to connection apparatus for usewith seismic braces. In particular, the present invention relates toconnection apparatus which prevent seismic and gravitational loads onsteel structural frames from being applied nonaxially to seismic braces.By way of example, the connection apparatus may allow the brace to pivotrelative to a structural frame.

2. Background of Related Art

In many areas of the world, particularly seismically active areas, largebuildings and other structures may be subjected to seismic loads. Inorder to prevent structures from being damaged by seismic loads,particularly the vibrations that follow the application of seismic loadsto structures, or to at least reduce the amount of damage that seismicloading may cause to such structures, various shock-absorption deviceshave been developed.

One such shock absorption device, which is useful with steel structuralframes, is commonly referred to as a “seismic brace.” As shown in FIG.1, a pair of seismic braces 10 is often arranged within each “bay” 32 ofa steel structural frame 30, each bay 32 typically being formed by anadjacent pair of substantially horizontally oriented steel beams 34(e.g., beams 34 u, 34L shown in FIG. 1) and an adjacent pair ofsubstantially vertically oriented steel columns 36. Bottom corners 38 ofeach bay 32 are formed at junctions between a lower substantiallyhorizontally oriented steel beam 34L and the substantially verticallyoriented steel columns 36 at each side of bay 32. Lower ends 12L ofseismic braces 10 are typically secured at opposite bottom corners 38 ofbay 32. Upper ends 12 u of seismic braces 10 are typically secured to anupper substantially horizontally oriented steel beam 34 u at adjacent,substantially central locations thereof. As such, the two seismic braces10 within a bay 32 of steel structural frame 30 are arranged in aninverted “V” configuration. Other, similar arrangements of seismicbraces are also known, including “V” configurations, alternative “V” andinverted “V” configurations, a single, diagonally oriented seismic brace10 in each bay 32 and another, oppositely oriented seismic brace 10 inthe next laterally adjacent bay 32 (i.e., such that seismic braces 10 intwo adjacent bays 32 form a “V” or inverted “V”), and the like. Byarranging seismic braces 10 in this manner, when a seismic, orearthquake, load is applied to the structure of which steel structuralframe 30 is a part, typically by shearing bay 32 in the directions ofarrows 40 and 42, one seismic brace 10 a of a pair will be subjected toa compressive load, depicted by arrows 44, while a tensile load,illustrated by arrows 46, will be applied to the other seismic brace 10b.

Conventionally, seismic braces have been rigidly secured to the beams 34and/or columns 36 of steel structural frames 30. FIGS. 2 through 2Billustrate an exemplary conventional connection, which includes the useof planar gusset plates 15 that are welded into place relative to a beam34 and/or a column 36 and which have perpendicular extensions 16 weldedto each side thereof. As shown in FIG. 2A, a cross-section takenperpendicular to the planes of both gusset plate 15 and extensions 16thereof has a generally cruciform shape and, thus, four interior corners17. Thus, each gusset plate 15 is configured complementarily to theexposed end 12 of a yielding core 11 (FIG. 1) of a seismic brace 10(FIG. 1), which also typically has a cross-section, taken transverse tothe length thereof, that is generally cruciform in shape and, thus,includes four interior corners 13 that extend along the length thereof,as shown in FIG. 2B. The cross-section of an exposed end 12 of ayielding core 11 of a seismic brace 10 and the corresponding features ofthe cross-section taken through gusset plate 15 and extensions 16thereof may have substantially the same dimensions. A rigid connectionbetween these two elements is typically effected by way of intermediatesecuring elements 19, which are typically referred to as “spliceplates,” positionable across portions of both an exposed end 12 and agusset plate 15/extension 16, within corresponding interior corners 13and 17. Each intermediate securing element 19 includes apertures 20, 21formed therethrough, which respectively align with correspondingapertures 14 formed through exposed ends 12 of yielding core 11 andapertures 18 formed through gusset plate 15 and extensions 16 therefrom.Apertures 14, 18, 20, and 21 are typically configured to receive bolts22, which, along with complementarily threaded nuts 23, secureintermediate securing elements 19 in place with respect to both gussetplates 15 and exposed ends 12 of yielding core 11, thereby securingseismic braces 10 into place relative to steel structural frame 30.

A seismic brace 10 (FIG. 1) is secured to a steel structural frame 30 byaligning exposed ends 12 of a yielding core 11 (FIG. 1) of each seismicbrace 10 with a corresponding gusset plate 15 that has already beensecured to one or more of a beam 34 and/or a column 36 of steelstructural frame 30, as well as with extensions 16 that have beensecured to that gusset plate 15. Intermediate securing elements 19 arethen positioned within interior corners 13 and 17, then bolted (e.g.,with bolts 22 and complementarily threaded nuts 23) to gusset plate 15,extensions 16 therefrom, and exposed end 12. As shown, the connection ofexposed ends 12 to gusset plate 15 is typically established by way offour intermediate securing elements 19 which have L-shapedcross-sections, taken transverse to the lengths thereof.

Referring again to FIG. 1, in addition to applying loads axially toseismic braces as a result of the shear generated by seismic andgravitational loads, rigid connections of this type typically transferadditional shears and moments, which are generated as a seismic brace 10drifts laterally. Application of shear and moment to a yielding core 11of a seismic brace 10 along vectors which are not located in a plane ofbay 32 undesirably causes a bending moment and shear stress to beapplied to yielding core 11, which, along with compressive loads appliedthereto, results in a so-called “combined stress” that is greater on oneside of yielding core 11 than on the other and that may cause seismicbrace 10 to buckle in an unintended direction. When such bucklingoccurs, seismic brace 10 is no longer useful for either shock absorptionor structural support.

Thus, a connection apparatus which substantially isolates a seismicbrace from nonaxially oriented loads, as well as that reinforces orisolates the seismic brace from shears and moments that occur as aseismic brace drifts from a plane of a bay of a steel structural framein which the seismic brace is located, would be an improvement over theexisting art of which the inventors are aware.

SUMMARY OF THE INVENTION

A connection apparatus according to the present invention includes afirst member, or frame-side member, which is configured to be secured toa structural frame, a second member, or brace-side member, which isconfigured to be secured to a core member of a seismic brace, and acoupling member. The frame-side member and brace-side member bothinclude coupling elements which are configured to receive or to bereceived by complementary portions of the connection member.

In an exemplary embodiment, the frame-side member of the inventiveconnection apparatus may comprise a substantially planar gusset plate.The gusset plate of the frame-side member is configured to be weldedinto a corner formed at a junction between two structural steel framemembers. The gusset plate includes an aperture, which is substantiallycircular in shape, formed therethrough. The brace-side member mayinclude two knife plates which are spaced apart from one another asufficient distance that the gusset plate may be interleaved therewith.Both elements of the brace-side member also include apertures, which arein alignment with one another and alignable with the aperture of theframe-side member. The apertures of the elements of the brace-sidemember may have substantially the same size and configuration (e.g.,substantially circular) as the aperture of the frame-side member. Uponassembly of the frame-side and brace-side members with the apertures insubstantial alignment, the coupling member, which may have asubstantially cylindrical central section, may be introduced into theapertures and secured in place relative to the frame-side and brace-sidemembers, thereby coupling the frame-side and brace-side members of theconnection apparatus to one another.

The coupling member of the connection apparatus may be held in place byway of enlarged heads at the ends thereof, bent regions at the endsthereof, securing elements that extend through apertures near the endsthereof, transversely to the length of the coupling member (e.g., likecotter pins), or by other position-retaining means.

The knife plates of the brace-side member are secured in place relativeto a load-bearing member, or “core,” of a seismic brace. For example,the knife plates may be welded directly to the core or to anintermediate member which is, in turn, welded to the core. Thesearrangements facilitate the positioning of an end of a yielding corecloser to the structural steel frame than do conventional, rigidconnections, which typically consume a significant portion of the fixeddistance between brace connection locations. Thus, connection apparatusaccording to the present invention may facilitate the use of seismicbraces which include yielding cores that are longer than the yieldingcores of conventional seismic braces that may be used at the samelocation of a structural steel frame. As is well known in the art, anincrease in the length of a yielding core means that the strain rate onthe yielding core will be less, resulting in a fatigue life which islonger than the fatigue life of a similar brace secured at a similarlocation using conventional, rigid connection apparatus.

Additionally, a connection apparatus according to the present inventionmay include a collar with one or more members that extend over ajunction between the brace-side member and the end of a seismic brace onwhich the connection apparatus is used. By way of example only, a firstend of each member of a collar may be secured to one or both of aportion of the brace-side member (e.g., the knife plates or intermediatemember) or to the core of a seismic brace with which the connectionapparatus is used, while a second end of each collar member may bepositioned adjacent to an external shell, or shell, sleeve, or tubeexterior, or other exterior surface of the seismic brace. The collar maybe permitted to slide longitudinally relative to the external sleeve asthe yielding core is compressed and elongated. It is currently preferredthat at least a portion of the collar member extend over andsubstantially parallel to an end portion of the external shell or otherexterior surface of the seismic brace.

Such a connection apparatus may be used with a variety of types ofcompression and tension-type seismic braces, including those withsingle, somewhat planar yielding cores, as well as those with multiplecores. The collar of the connection apparatus may also be used withother types of connection apparatus, including known, rigid connectionapparatus for seismic braces. The collar is particularly useful withseismic braces that include axial-load-bearing cores that are surroundedby buckling-limiting material encased by external sleeves.

In another embodiment, the frame-side member of a connection apparatusaccording to the present invention may include a pair of gusset plates,while the brace-side member of such a connection apparatus comprises anexposed end of a core of a seismic brace or an extension therefrom whichis rigidly secured thereto. The gusset plates of the frame-side memberare configured to be secured to a steel structural frame in spaced-apartrelation to one another and oriented substantially parallel to eachother, with an aperture formed through each gusset plate being insubstantial alignment with an aperture of the other gusset plate. Thebrace-side member is configured to be positioned between the gussetplates such that an aperture thereof substantially aligns with thesubstantially aligned apertures of the gusset plates. Upon arranging andassembling the frame-side and brace-side members in this manner, acoupling member, such as an elongate member with a substantiallycylindrical center section (e.g., a pin, bolt, etc.), may be introducedinto the substantially aligned apertures.

Of course, other arrangements and configurations of apparatus forconnecting seismic braces to steel structural frames are also within thescope of the present invention. For example, another embodiment ofconnection apparatus that incorporates teachings of the presentinvention may comprise a ball-and-socket type connection apparatus. Thefirst member, or frame-side member, of such a connection apparatus,which is securable to a steel structural frame, may comprise a socket.The socket may, for example, be in the form of an aperture with aconcave edge. The coupling member of such a connection apparatus maycomprise a ball, which may be spherical in shape, an oblong spheroid,disc-shaped, or otherwise configured to fit within the socket of theframe-side member and rotate somewhat relative to the frame-side member.The coupling member may also include one or more pins protruding fromopposite sides thereof. The second member, or brace-side member, of aball-and-socket type connection apparatus includes a pair ofsubstantially planar members which are spaced apart a sufficientdistance that the ball of the coupling member may be positionedtherebetween. An aperture formed through each substantially planarmember is configured to receive a portion of a pin protruding from theball and, thus, facilitates hinged movement of the brace-side member andof a seismic brace to which the brace-side member is secured relative toone or both of the ball and the frame-side member of the connectionapparatus.

In use, the frame-side member of a connection apparatus of the presentinvention is secured to a steel structural frame, such as in a cornerformed between conjoined horizontal beams and vertical steel columns.Continuing with the above examples, this may be effected by welding orotherwise securing one or more gusset plates into such a corner. Thebrace-side member of the connection apparatus, which, preferably, hasalready been secured to or formed at the end of a core of a seismicbrace, is then positioned appropriately relative to the frame-sidemember, such that apertures of the frame-side and brace-side members aresubstantially mutually aligned. A coupling member is then introducedinto the aligned apertures so as to be positioned within each of thesubstantially aligned apertures of the frame-side and brace-sidemembers. The coupling member is then secured in this position to preventinadvertent removal thereof from the apertures. The opposite end of theseismic brace may then be similarly secured to another (higher or lower)horizontally extending steel beam. Alternatively, another type ofconnection, including a rigid, conventional connection, may be used tosecure the other end of the seismic brace to the other horizontallyextending beam. As a single pin is secured in position rather thanseveral bolts, as required by conventional, rigid connection apparatus,erection of a seismic brace that includes a connection apparatusaccording to the present invention is simpler and faster than erectionwith conventional, rigid connection apparatus.

When a building that includes a frame with one or more seismic bracesconnected thereto by way of a connection apparatus of the presentinvention is subjected to a load, such as that generated by shock waves(e.g., seismic shock waves, high winds, etc.), the connection apparatusand the adjacent end of the seismic brace are substantially isolatedfrom external moments that result from movement of the seismic brace outof the plane of the bay of a steel structural frame in which the seismicbrace is located. The collar resists in-plane and out-of-plane momentson the exposed portions of the core of the seismic brace, as well as ofthe remainder of the connection apparatus, thereby permitting onlysubstantially axial loads to be applied to the core, providing supportto the core and the remainder of the connection apparatus, andpreventing weak axis buckling of the core. In addition, the connectionapparatus reduces the moments and shears that result from theapplication of gravity and earthquake loads to a steel structural frameby providing a larger moment of inertia at the ends of the core of aseismic brace. As a result, the connection element substantially limitsthe forces that are applied to the seismic brace to those which may beproperly absorbed thereby.

As a further result of providing a nonrigid connection, the likelihoodof a connection apparatus according to the present invention beingdamaged when subjected to gravity and earthquake loads is much lowerthan the likelihood of a conventional rigid connection being damaged.Thus, following failure due to absorption of excessive earthquake loads,a seismic brace which is at least partially secured to a steelstructural frame by way of one or more of the inventive connectionapparatus may still have some load-bearing capabilities and, thus,provide some structural support to a steel structural frame, whereasseismic braces that are secured in place by weakened conventional rigidconnections would be less likely to provide such support.

Other features and advantages of the present invention will becomeapparent to those of ordinary skill in the art through a considerationof the ensuing description, the accompanying drawings, and the appendedclaims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, which illustrate various features of exemplaryembodiments of the present invention:

FIG. 1 is a schematic representation of a bay of a steel structuralframe with a pair of seismic braces, which are positioned within the bayin a conventional fashion, coupled to the steel structural frame;

FIG. 2 depicts an example of a conventional rigid connection between asteel structural frame and an exposed end of a yielding core of aseismic brace;

FIG. 2A is a cross-section taken along line 2A-2A of FIG. 2;

FIG. 2B is a cross-section taken along line 2B-2B of FIG. 2;

FIG. 3 is side view of an example of a seismic brace with which anonrigid connection apparatus that incorporates teachings of the presentinvention may be used, as well as an exemplary embodiment of nonrigidconnection apparatus;

FIG. 4 is a cross-section taken through line 414 of FIG. 3;

FIG. 5 is a side view of the embodiment of nonrigid connection apparatusshown in FIG. 3;

FIG. 6 is a perspective view of a brace-side member of the nonrigidconnection apparatus of FIGS. 3 and 5;

FIG. 7 is a perspective view of a frame-side member of the nonrigidconnection apparatus of FIGS. 3 and 5;

FIG. 8 is a perspective assembly view of another embodiment of nonrigidconnection apparatus according to the present invention;

FIG. 9 is a perspective view of the nonrigid connection apparatus shownin FIG. 8;

FIG. 10 is a top view of the nonrigid connection apparatus of FIGS. 8and 9;

FIG. 11 is a cross-sectional representation of a brace-side member ofyet another embodiment of nonrigid connection apparatus according to thepresent invention;

FIG. 12 is a perspective assembly view of a ball-and-socket embodimentof nonrigid connection apparatus incorporating teachings of the presentinvention, which includes a coupling element comprising a ball;

FIG. 13 is a cross-section taken along line 13-13 of FIG. 12;

FIG. 13A a cross-sectional representation of a variation of the couplingelement of the nonrigid connection apparatus shown in FIGS. 12 and 13;

FIG. 13B is a cross-sectional representation of another variation of thecoupling element of the nonrigid connection apparatus shown in FIGS. 12and 13, which comprises a disc rather than a ball;

FIG. 14 is a side view of the nonrigid connection apparatus of FIGS. 12and 13;

FIG. 15 is a top view of the nonrigid connection apparatus of FIGS. 12through 14;

FIG. 16 is a side view of an example of use of the brace-side member ofthe nonrigid connection apparatus depicted in FIGS. 3-7 with a pluralityof seismic braces; and

FIGS. 17-19 are cross-sectional representations of various examples ofmultiple-brace arrangements that may be used as shown in FIG. 16.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 3 and 4, a seismic brace 100 that incorporatesteachings of the present invention is depicted. In the illustratedexample, seismic brace 100 is a single-core, compression and tensionmember which includes an elongate, substantially hollow exterior shell102, a buckling-limiting member, which is also referred to herein as“containment 106,” within exterior shell 102, and an elongate yieldingcore 110 positioned substantially centrally within and extendingcompletely along the length of containment 106. The depicted yieldingcore 110 has a rectangular, somewhat planar cross-section, takentransverse to the length thereof, and includes ends 113 and 114 whichextend beyond corresponding ends 103, 104 of exterior shell 102.Yielding core 110 is positioned within an aperture 108 that extendssubstantially through containment 106 and includes at least one surface111 which is spaced apart from an interior surface 107 of containment106 by way of a readily compressible medium 109, such as a polymer, air,or the like. Although FIG. 3 depicts a particular embodiment of seismicbrace 100, which comprises a single-core member that may be subjected tocompressive and tensile loads, other types of seismic braces, includingall-steel seismic braces which lack a buckling-limiting member, may alsobe used in accordance with teachings of the present invention.

With continued reference to FIG. 3, a brace-side member 130 of anexemplary embodiment of nonrigid connection apparatus 120 according tothe present invention is located at at least one end 113, 114 ofyielding core 110. Brace-side member 130 is also referred to herein as asecond member, or simply as a member, of nonrigid connection apparatus120 and as a nonrigid connection element.

As shown in FIG. 5, brace-side member 130 includes an intermediatemember, in this case an end plate 132, which is secured to end 113, 114of yielding core 110, such as by welds 134. Brace-side member 130 alsoincludes two knife plates 136 and 138 secured to and extending from endplate 132 in mutually parallel relation. Welds 140 or other known fixingmeans may secure knife plates 136 and 138 to end plate 132. As shown,knife plates 136 and 138 may extend in substantially the same directionas seismic brace 100 (FIGS. 3 and 4) and may be oriented substantiallyperpendicular to end plate 132.

Turning to FIG. 6, each knife plate 136, 138 of brace-side member 130 ofnonrigid connection apparatus 120 (FIGS. 3 through 5) includes anaperture 137, 139, respectively formed therethrough. Apertures 137 and139, which are both configured to receive a central portion 162 (FIG. 5)of a coupling member 160 (FIG. 5) of nonrigid connection apparatus 120,are in substantial alignment with one another.

With briefly returned reference to FIG. 3, knife plates 136 and 138 ofbrace-side member 130 are spaced a sufficient distance apart from oneanother that a corresponding feature (e.g., gusset plate 152 of FIG. 7)of a frame-side member 150 of nonrigid connection apparatus 120 may bepositioned therebetween.

As depicted in FIG. 7, an exemplary embodiment of a frame-side member150 of nonrigid connection apparatus 120 (FIGS. 3 through 5) is shown.Frame-side member 150 is also referred to herein as a first member, orsimply as a member, of connection apparatus 120 or as a nonrigidconnection element. The illustrated frame-side member 150 comprises asingle, substantially planar gusset plate 152, which is configured to befixed in place relative to a member of a steel structural frame 30, suchas one or more of a conjoined beam 34 and/or column 36 thereof. Whilegusset plate 152 is shown in the illustrated example as being secured ina corner formed at a junction between a horizontally oriented beam 34and a vertically oriented column 36, gusset plate 152 maybe secured toany suitable surface (i.e., within a bay 32 of steel structural frame30) of a single beam 34 or column 36. Also, while FIG. 7 depicts gussetplate 152 as being held in place by welds 153, other fixing means forsecuring gusset plate 152 into position (e.g., rivets, bolts, etc., forsecuring gusset plate 152 to a lip (not shown) protruding from beam 34and column 36) are also within the scope of the present invention.

The dimensions of gusset plate 152 and the type of fixing means used tosecure the same to a steel structural frame 30, including the height,length, and thickness thereof, are configured to withstand predeterminedamounts of load, moment, and other stresses. Accordingly, the dimensionsof gusset plate 152 depend at least partially upon the material (e.g.,the type of steel) from which gusset plate 152 is fabricated, as well asthe size of seismic brace 100 (FIG. 3) to be used therewith, thelocation of a steel structural frame 30 at which seismic brace 100 is tobe used, and other factors, as known in the art.

Gusset plate 152 of frame-side member 150 of connection apparatus 120includes an aperture 154 therethrough. Aperture 154 may havesubstantially the same internal crosswise dimensions (e.g., radius) asapertures 137 and 139 (FIG. 6) of substantially planar knife plates 136and 138, respectively, of brace-side member 130 of nonrigid connectionapparatus 120. Upon positioning substantially planar knife plates 136and 138 on opposite sides of a gusset plate 152 which has been fixedinto position relative to a steel structural frame 30 into anappropriate assembled relationship, apertures 137 and 139 ofsubstantially planar knife plates 136 and 138, respectively, are insubstantial alignment with aperture 154 of gusset plate 152.

Referring again to FIG. 5, apertures 137, 139, and 154 are sized andconfigured to receive a central portion 162 of a coupling member 160 ofnonrigid connection apparatus 120. When positioned within apertures 137,139, and 154 of assembled brace-side and frame-side members 130 and 150,respectively, coupling member 160 nonrigidly couples brace-side member130 and frame-side member 150 in the assembled relationship thereof. Inthis case, the nonrigid coupling is a hinged connection, at whichmovement may occur in substantially a single plane and at asubstantially single pivot point.

Coupling member 160 is held in place within apertures 137, 139, and 154by position-retaining elements 164, such as enlarged heads or nuts atthe ends thereof, bent regions at the ends thereof, securing elementsthat extend through apertures near the ends thereof, transversely to thelength of the coupling member 160 (e.g., like cotter pins), or the like.Of course, combinations of different types of position-retainingelements 164 may be used to secure a coupling member 160 into placerelative to frame-side member 150 and brace-side member 130 of nonrigidconnection apparatus 120.

With continued reference to FIG. 5, a support collar 170 is alsodepicted. Support collar 170 includes a distal end 175, which isconfigured to be positioned at or near brace-side member 130 of nonrigidconnection apparatus 120, and a proximal end 176, which is configured toextend at least partially over an end 103, 104 of exterior shell 102.Proximal end 176 of support collar 170 may be permitted to sliderelative to a length of exterior shell 102. As proximal end 176 ofsupport collar 170 is to be positioned over an end 103, 104 of exteriorshell 102, at least the portion of a hollow center 173 thereof which isto receive an end 103, 104 of exterior shell 102 has internal dimensionswhich are roughly the same as or slightly greater than the correspondingexternal dimensions of that end 103, 104. When properly positioned overan end 113, 114 of a yielding core 110 of a seismic brace 100 (FIGS. 3and 4), support collar 170 substantially isolates yielding core 110 fromexternal shear and moment, instead absorbing some of the external shearand moment and transmitting external shear and moment to exterior shell102. Thus, such positioning of seismic brace 100 isolates ends 113, 114against loads that are placed transversely on seismic brace 100 withrespect to the axis or length thereof.

The exemplary support collar 170 which is shown in FIG. 5 includes firstand second halves 171 and 172, respectively. When assembled, first half171 and second half 172 form an elongate structure with a substantiallyrectangular cross-section taken transverse to the length of theassembled support collar 170 and a hollow center 173. First half 171 andsecond half 172 may be secured to one another by any suitable fixingmeans, including, without limitation, welds, rivets, nuts and bolts, andthe like. As an alternative to the depicted embodiment of support collar170, support collar 170 may comprise a single piece. Other variations ofsupport collars that incorporate teachings of the present invention and,thus, that are within the scope of the present invention include supportcollars with more than two pieces. Also, support collars that include aplurality of elements which are not secured directly to one another but,rather, which are secured to a seismic brace 100 (FIGS. 3 and 4) and abrace-side member 130 of a nonrigid connection apparatus 120 are withinthe scope of the present invention.

FIGS. 8 through 10 depict another exemplary embodiment of nonrigidconnection apparatus 120′ according to the present invention.

As shown in FIGS. 8 through 10, a brace-side member 130′ of nonrigidconnection apparatus 120′ includes a single, knife plate 136′ with anaperture 137′ formed therein. Knife plate 136′ may be secured, byappropriate fixing means, to an intermediate member, such as an endplate 132′, that has been secured to an end 113, 114 of a yielding core110 of a seismic brace 100. Alternatively, knife plate 136′ may besecured directly to end 113, 114.

Frame-side member 150′ of nonrigid connection apparatus 120′ includestwo substantially planar gusset plates 152′. Each gusset plate 152′includes an aperture 154′ formed therethrough. Gusset plates 152′ offrame-side member 150′ are spaced apart from one another and oriented insubstantially parallel relation to one another with apertures 154′thereof in substantial axial alignment. The spacing between gussetplates 152′ is sufficient to permit the insertion of knife plate 136′therebetween.

When knife plate 136′ is positioned between gusset plates 152′ in anappropriate assembled relationship thereof, aperture 137′ of knife plate136′ and apertures 154′ of gusset plates 152′ are in substantial axialalignment with one another. Accordingly, a coupling member 160 ofnonrigid connection apparatus 120′ may be introduced into apertures 137′and 154′ and secured in place relative to both brace-side member 130′and frame-side member 150′ of nonrigid connection apparatus 120′, asdescribed previously herein with reference to FIG. 5.

FIGS. 8 and 9 depict another exemplary support collar 170′ that may beused with nonrigid connection apparatus 120′ or any other embodiment ofnonrigid connection apparatus that incorporates teachings of the presentinvention. Support collar 170′ includes four elongate members 172′, withcross-sections taken transverse to the length thereof having an “L”shape. A first end 173′ of each elongate member 172′ is secured (e.g.,by welds or other suitable fixing means) to a corner 133′ of end plate132′, while an opposite, second end 174′ of each elongate member 172′ issecured to an end 103 of exterior shell 102. As there are four elongatemembers 172′ in the depicted example, one elongate member 172′ extendsbetween each corner 133′ of end plate 132′ and a corresponding end 103of exterior shell 102.

In another, similar embodiment of nonrigid connection apparatus 120″,shown in FIG. 11, brace-side member 130″ comprises an end 113″, 114″ ofyielding core 110″ of seismic brace 100″. An aperture 137″ formedthrough end 113″, 114″ is configured to receive a central portion 162(FIG. 5) of a coupling member 160 of nonrigid connection apparatus 120″.

A frame-side member 150′ of nonrigid connection apparatus 120″ is thesame as that shown and described previously herein with reference toFIGS. 8 through 10 and, thus, includes a pair of gusset plates 152′.Gusset plates 152′ of frame-side member 150′ are arranged substantiallyparallel to one another with apertures 154′ thereof in substantial axialalignment and are spaced apart a sufficient distance that end 113″, 114″of yielding core 110″ may be positioned therebetween. Upon positioningend 113″, 114″ between gusset plates 152′ and substantially axiallyaligning aperture 137″ with apertures 154′, coupling member 160 may beplaced within the substantially aligned apertures 154′ and 137″ so as tononrigidly connect end 113″, 114″ to frame-side member 150′, asdescribed previously herein with reference to FIGS. 5 and 8 through 10.Coupling member 160 may then be secured in place, as describedpreviously herein with reference to FIGS. 5 and 8 through 10.

A support collar 170″ which is configured to be used with brace-sidemember 130″ includes an end plate 177″ with a slot 178″ formedtherethrough to receive end 113″, 114″ of yielding core 110″. End plate177″ is positioned at an intermediate location along end 113″, 114″ ofyielding core 110″.

In addition to being useful with nonrigid connection apparatus of thetypes described herein, support collars (e.g., support collar 170, 170′,170″) that incorporate teachings of the present invention may also beused with other types of connection apparatus, including other nonrigidconnection apparatus, as well as the nonrigid connection apparatus(e.g., gusset plate bolted to brace ends with cross-sections taken alongthe lengths thereof that are cruciform in shape).

Another exemplary embodiment of nonrigid connection apparatus 220 thatincorporates teachings of the present invention is depicted in FIGS. 12through 15.

As shown in FIG. 12, nonrigid connection apparatus 220 includes abrace-side member 230, which is configured to be secured to a seismicbrace 100 (FIGS. 3 and 4), and a frame-side member 250, which isconfigured to be secured to a steel structural frame. Nonrigidconnection apparatus 220 also includes a coupling member 260, whichnonrigidly secures brace-side member 230 to frame-side member 250 and,thus, a seismic brace 100 to a steel structural frame 30. As depicted,nonrigid connection apparatus 220 comprises a ball-and-socket typejoint, with frame-side member 250 comprising the socket, coupling member260 comprising the ball, and brace-side member 230 being pivotallysecured to the ball of coupling member 260.

As shown in FIGS. 12 and 13, frame-side member 250 may comprise a pairof substantially planar gusset plates 252 with large apertures 254formed therein. Each aperture 254 includes a concave edge 256, thecurvature of which is configured to complement at least a portion of anexterior surface of coupling member 260 so as to retain coupling member260 within aperture 254. Of course, the thickness of gusset plate 252,the sizes of apertures 254, and the curvatures of concave edges 256 maybe configured to retain coupling member 260 under seismic andgravitational loads and, thus, when tensile and compressive loads arebeing applied to seismic brace 100 (FIGS. 3 and 4).

Gusset plate 252 may be secured to one or more of a beam 34 and a column36 of a steel structural frame 30 as known in the art, such as by welds,nuts and bolts, rivets, or the like.

FIGS. 12 and 13 illustrate coupling member 260, which includes a ball262. As shown, ball 262 is spheroid in shape, comprising a sphere,although oblong spheroids are also within the scope of the presentinvention, as are spheres and spheroid structures that havesubstantially opposite planar surfaces. Ball 262 is configured to beintroduced into aperture 254 of frame-side member 250 in such a way thatan engaging region 263 of ball 262 is engaged by concave edges 256 ofapertures 254, between gusset plates 252 and, thus, retained at leastpartially within apertures 254.

The exemplary coupling member 260 depicted in FIGS. 12 and 13 alsoincludes an aperture 264 extending axially through ball 262, as well asan elongate pin 266 positioned within aperture 264 so as to extendcompletely through ball 262 and to protrude from opposite sides thereof.Alternatively, as shown with respect to coupling member 260′ of nonrigidconnection apparatus 220′ in FIG. 13A, two pins 266′ may be secured toopposite sides of a ball 262′ (e.g., by threadingly engaging apertures268′ in opposite sides of ball 262′, as shown, by welds, etc.).

Of course, variations of coupling members are also within the scope ofthe present invention, including, without limitation, coupling member260″ depicted in FIG. 13B, which includes a disc-shaped element 262″with a coupling portion comprising a rounded ridge 263″ extending aroundat least a portion of the outer circumference thereof. Rounded ridge263″ is configured to be engaged by a concave edge 256″ of an aperture254″ of frame-side member 250″ of nonrigid connection apparatus 220″ insuch a way that disc-shaped element 262″ may at least partially rotateabout its axis A within aperture 254″, as well as move laterally, intoand out of a plane P in which gusset plate 252″ is located, as shown byarrows 269.

Like coupling members 260 and 260′, coupling member 260″ may include oneor more pins 266″ protruding from opposite sides of disc-shaped element262″. As shown, each pin 266″ may be positioned so as to extendsubstantially along axis A of disc-shaped element 262″.

With returned reference to FIG. 12, as well as reference to FIGS. 14 and15, brace-side member 230 of nonrigid connection apparatus 220 may beconfigured substantially as brace-side member 130 described above withreference to FIGS. 3 through 6. Thus, brace-side member 230 may includean end plate 232, which is secured to end 113, 114 of yielding core 110(FIGS. 3 and 4), to which two knife plates 236 and 238 are secured.Knife plates 236 and 238 extend from end plate 232 in mutually parallelrelation. As shown, knife plates 236 and 238 may extend in substantiallythe same direction as seismic brace 100 (FIGS. 3 and 4) and may beoriented substantially perpendicular to end plate 232. Knife plates 236and 238 are spaced a sufficient distance apart from one another thatframe-side member 250 and ball 262, 262′ or disc-shaped element 262″ ofa respective coupling member 260, 260′, 260″ may be positionedtherebetween.

Each knife plate 236, 238 of brace-side member 230 of nonrigidconnection apparatus 220 includes an aperture 237, 239 formedtherethrough. Apertures 237 and 239 are both configured to receive aportion of a pin 266, 266′, 266″ (FIGS. 13, 13A, and 13B, respectively)of a complementary coupling member 260, 260′, 260″ in such a way thatbrace-side member 230 and, thus, a seismic brace 100 to which brace-sidemember 230 is secured, may pivot about an axis A defined by pins 266,266′, 266″.

As is apparent from the foregoing description, nonrigid connectionapparatus 220, 220′, 220″ allow a seismic brace 100 to pivot relative toframe-side member 250 in more than one plane. Accordingly, nonrigidconnection apparatus 220, 220′ and 220″ substantially isolate seismicbrace 100 from shear, moment, and loads that are nonaxial to seismicbrace 100.

Turning now to FIGS. 16-19, use of a brace-side member 130 of a nonrigidconnection apparatus according to the present invention with a pluralityof seismic braces 100 is depicted. In FIG. 16, end plate 132 ofbrace-side member 130 is depicted as having yielding cores 110 of atleast two seismic braces 100 secured thereto. Support collar 170surrounds the adjacent end 103, 104 of exterior shell 102 of eachseismic brace 100. FIG. 17 depicts a multi-brace embodiment thatincludes two seismic braces 100 with yielding cores 110 that are in amutually parallel arrangement. FIG. 18 shows another multi-braceembodiment that includes three seismic braces 100 and 100′ that arearranged in a linear fashion. FIG. 19 illustrates yet anothermulti-brace embodiment that includes four seismic braces 100 in atwo-by-two arrangement.

Multi-brace embodiments of the present invention are not limited to thedepicted nonrigid connection apparatus 120, but may also be used withother embodiments of nonrigid connection apparatus that incorporateteachings of the present invention. Moreover, while each of the seismicbraces 100, 100′ shown in FIGS. 16-19 includes an exterior shell 102within which a yielding core 110 and a surrounding containment 106 aredisposed, other types of seismic braces may also be secured tobrace-side member 130 without departing from the scope of the presentinvention. In addition, it is within the scope of the present inventionto secure two or more different types of seismic braces to the samebrace-side member (e.g., brace-side member 130) of a nonrigid connectionapparatus (e.g., nonrigid connection apparatus 120 (FIG. 5))incorporating teachings of the present invention.

Although the foregoing description contains many specifics, these shouldnot be construed as limiting the scope of the present invention, butmerely as providing illustrations of some of the presently preferredembodiments. Similarly, other embodiments of the invention may bedevised which do not depart from the spirit or scope of the presentinvention. Moreover, features from different embodiments of theinvention may be employed in combination. The scope of the invention is,therefore, indicated and limited only by the appended claims and theirlegal equivalents, rather than by the foregoing description. Alladditions, deletions, and modifications to the invention, as disclosedherein, which fall within the meaning and scope of the claims are to beembraced thereby.

1. A seismic brace, comprising: an elongate, substantially hollowexterior shell; a buckling-limiting element within said exterior shell;at least one yielding core including: a central region located centrallywithin said buckling-limiting element and at least partially spacedapart therefrom; and two end regions at opposite ends of said centralregion, said two end regions extending beyond ends of saidbuckling-limiting element and said exterior shell; at least oneconnection element at at least one end region of said two end regions ofsaid at least one yielding core; and a support collar laterallysurrounding at least a portion of a length of said at least one endregion and including: a first end secured to a portion of said at leastone connection element; and a second end overlapping at least an endportion of said exterior shell.
 2. The seismic brace of claim 1, whereinsaid at least one yielding core comprises a substantially planar member.3. The seismic brace of claim 1, wherein each end region of said two endregions of said at least one yielding core is substantially planar. 4.The seismic brace of claim 1, wherein said at least one connectionelement comprises at least one end region of said two end regions ofsaid at least one yielding core.
 5. The seismic brace of claim 1,wherein said at least one connection element is secured to at least oneend region of said two end regions of said at least one yielding core.6. The seismic brace of claim 5, wherein said at least one connectionelement comprises: an end plate secured to said at least one end regionof said at least one yielding core; and a plurality of substantiallyplanar members extending from said end plate and oriented substantiallyperpendicular to said end plate and substantially parallel to oneanother.
 7. The seismic brace of claim 6, wherein each substantiallyplanar member of said plurality of substantially planar members includesan aperture formed therethrough, each said aperture being in substantialalignment with apertures of each other substantially planar member ofsaid plurality of substantially planar members.
 8. The seismic brace ofclaim 7, further comprising: an elongate coupling element configured tobe received within apertures of each of said plurality of substantiallyplanar members and within an aperture of at least one complementaryconnection element secured to a member of a steel structural frame so asto pivotally secure at least one end of the seismic brace to said steelstructural frame.
 9. The seismic brace of claim 1, comprising aplurality of elongate, substantially hollow exterior shells, eachincluding a buckling-limiting element and at least one yielding coretherein.